SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cac44eb6275a22185a4cb15c7c31c06292bb799fe955c2461bef38cf6febecd' 
  AND token = 'n/RNqXTXT/wtfu+QhyW+cYlh1OszdHY28N3TUvbHQ4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}